A pacifist is somebody who is against . . . . . . . . war. A. a B. an C. the D. no article

The correct answer is D. no article.

A pacifist is somebody who is against war. The word “pacifist” is a noun, and nouns do not usually take articles. In this case, the word “war” is also a noun, so it does not need an article either.

The other options are incorrect because they are all articles. The article “a” is used before singular nouns that refer to a specific person or thing. The article “an” is used before singular nouns that begin with a vowel sound. The article “the” is used before singular nouns that refer to a specific person or thing that has already been mentioned.

In this case, the word “war” is a general noun that refers to any war.